Lactuca sativa var. capitata
head lettuce
Mediterranean basin (species origin); cultivated globally
Overview
Lactuca sativa var. capitata spp. encompasses crisphead (iceberg) and butterhead lettuce types in the family Asteraceae. Crisphead types form dense firm spherical heads 6-8 inches (15-20 cm) in diameter, with pale green tightly packed crisp leaves. Over 70% of US lettuce acreage is crisphead, primarily in California and Arizona. Days to maturity: 70-85 from direct sow (crisphead). Requires a long cool growing window of 70-85 days below 75°F (24°C), which makes the crisphead group challenging for home gardeners in warm climates. Bolts rapidly in heat. In the Pacific Northwest, seed is started indoors in late January, transplanted in March, and harvested in June. Susceptible to tipburn, bottom rot, and aphids.
Native Range
Lactuca sativa is derived from L. serriola, native to the Mediterranean basin.Suggested Uses
A common salad and sandwich lettuce. Crisp texture suits shredded salads and burger toppings. Stores 2-3 weeks refrigerated. Not suited to short-season or warm-summer climates without season extension.How to Identify
Appearance
Size & Dimensions
Height6" - 10"
Width/Spread10" - 1'
Reaches mature size in approximately 1 years
Bloom Information
Yellow flowers when bolting; harvest occurs before flowering since bolting turns leaves bitter.
Detailed Descriptions
Flower Description
Yellow; daisy-family composite; on bolting plants onlyFoliage Description
Pale green inner; medium green outer; thick crisp leaves; deciduousGrowing Conditions
Sun Requirements
Requires 4-8 hours of direct sunlight daily
• Full Sun: 6+ hours of direct sunlight
• Partial Shade: 3-6 hours of direct sunlight
• Full Shade: Less than 3 hours of direct sunlight
Care & Maintenance
Care Guide
Transplants are started 6-8 weeks before last frost. Spaced 12 inches (30 cm) apart. Full sun, moist soil at pH 6.0-7.0. Watered 1-1.5 inches (2.5-4 cm) per week. The crisphead group requires a sustained cool window of 70-85 days below 75°F (24°C). In short or warm growing seasons, butterhead and leaf types are more reliable.Pruning
No pruning is needed. Harvest takes the entire head when firm.Container Growing
✓ Suitable for container growing
Minimum container size: 5 gallons
✓ Toxicity
Non-toxicPlanting Guide
Planting Methods & Timing
Planting Method
transplant
Indoor Start
7 weeks before last frost
Direct Sow Timing
Early spring 2-4 weeks before last frost; again in late summer for fall harvest
Days to Maturity
70–85 days
Plant Spacing
12 inches